Oxidation behavior at 300–1000C of a (Mo,W)Si2-based composite containing boride

Journal article, 2010

The oxidation behavior of a (Mo,W)Si2 composite with boride addition was examined at 300–1000C for 24 h in dry O2. The oxidation kinetics was studied using a thermobalance, and the oxide scales were analyzed using a combination of electron microscopy (SEM/EDX, FIB, BIB) and XRD. Accelerated oxidation was found to occur between 500C and 675C, with a peak mass gain at 625C. The rapid oxidation is attributed to the vaporization of molybdenum oxide that leaves a porous and poorly protective silica layer behind. At higher temperature (700–1000C) a protective scale forms, consisting of a dense SiO2/ B2O3 glass.